A condensate pump is used in an HVAC system to collect condensate water from the evaporator of the HVAC system and to pump the condensate water through a drain line to a drain line outlet at a remote location for disposal. The drain line outlet is usually elevated above the condensate pump. Particularly, the condensate pump typically comprises a reservoir, an impeller pump for pumping the water out of the reservoir to the remote location through the drain line, and an electric motor to drive the impeller pump. Conventionally, a float detects the level of condensate water in the reservoir and activates control switches to control the operation of the electric motor and if necessary, to sound an alarm or shut off the HVAC system.
Condensate pumps are often located in extreme environments and subjected to moisture, heat, and cold. Moreover, condensate pumps are often installed in inaccessible locations where maintenance is difficult, and therefore reliability over many years is necessary. Further, the condensate pump should operate quietly and without excessive buildup of heat from the operation of the electric motor. In addition, the condensate pump should be able to inhibit the build up of slime and algae in the reservoir and drain line. The condensate pump should be able to break up clogs in the drain line. A condensate pump should also be able to detect an emergency near overflow condition, trigger alarms, and shut down the HVAC system if necessary.
In a conventional condensate pump, a mechanical float monitors and detects the water level within the reservoir. In response to movement of the float within the reservoir, associated float switches and a float control circuitry control the operation of the electric pump motor, trigger alarms, or shut down the HVAC system if necessary. The condensate pump float is in contact with the water in the reservoir and is subject to fouling from debris and algae buildup. A molded float has seams, which may fail causing the float to sink or malfunction. The float switch that is used to control the on/off operation of the electric motor is often a specialized and costly bi-stable snap-action switch. A conventional condensate pump that incorporates a safety HVAC shut off switch and/or or an alarm switch, in addition to the motor control switch, may have a separate float or linkage to operate the HVAC shutoff switch or the alarm switch further complicating the condensate pump. Further, conventional condensate pumps often require a float mechanism retainer to prevent shipping damage, and the float mechanism retainer must be removed prior to pump use.